1. Field of the Invention
The present invention relates to a method and apparatus for hygienically preparing dried pepper by continuously sterilizing and drying fresh pepper.
2. Description of the Related Art
In general, most red peppers are harvested between July and September every year in Korea. Thus, there is a need for a large scale storage or processing facility for storing such a large amount of pepper produced in a short period of time and providing dried pepper as needed. Pepper has a greater internal latent heat and higher post-harvest degradation rate than other products. Accordingly, a technique of inactivating enzyme autolysis is very important for a long-period storage of a large amount of fresh pepper. In particular, a drying process for preventing deterioration within a short period of time from harvest is needed for safe, long-period storage of a large amount of fresh pepper.
According to a conventional method for preparing dried pepper, fresh pepper is dried by the sun or static hot air without additional washing process. Thus, foreign materials adhering to fresh pepper or residual pesticides are not fully removed, and the fresh pepper is exposed to pathogenic microorganisms existing in the air. In addition, there is no hygiene control in the preparation of dry pepper, so a large number of microorganisms still remain on and in the pepper. The color and flavor of dried pepper vary according to the drying time and weather conditions during drying, etc. In view of this, the conventional method cannot ensure production of dried pepper having uniform color and flavor.
As a method for hygienically producing dried pepper, a method of sterilizing pepper by radiating gamma rays on the surface of pepper is known. Gamma ray radiation method is highly effective only in reducing the number of microorganisms, but not in removing other contamination sources excluding the microorganisms. Rather, for freeze-dried red pepper, color and flavor are changed by the gamma ray radiation, degrading the quality of the dried pepper.
Also, dried pepper powder is produced by washing fresh pepper with a high-pressure cleaning device, hot air drying, and grinding the dried pepper. However, because 1000 times more microorganisms exist in the flesh of pepper than in the skin, this drying method cannot be regarded as a hygienic method.
To solve the above-described problems, it is an object of the present invention to provide a method and apparatus for hygienically producing dried pepper, in which sterilizing and drying of fresh pepper are continuously carried out.
In an aspect of the object of the present invention, there is provided a method for hygienically preparing dried peppers by continuous sterilization and drying processes, comprising: screening fresh peppers, removing the stems of the peppers, and aging the peppers; washing the peppers to remove foreign materials and pesticide residue from the surfaces of the peppers; optionally sterilizing the surfaces of the washed peppers using a chemical sterilant solution; cutting and separating seeds from the washed or sterilized peppers; sterilizing the cut peppers using a chemical sterilant solution and/or high-temperature and high-pressure steam; drying the sterilized peppers by hot air or freeze-drying; and grinding the dried peppers into a product.
It is preferable that the step of aging of fresh peppers is performed for 1-3 days in a cool and well-ventilated place. This aging step improves color and hot taste of the peppers.
It is preferable that, before or after aging, after cutting and separating the seeds from the peppers, or after hot air drying, further comprising deep-freezing and storing the peppers. The step of deep-freezing and storing peppers ensures smooth processing of the hygienically clean peppers throughout the year by efficiently storing a bunch of peppers produced in a limited short period of time It is preferable that deep-freezing and storing the peppers is performed at a temperature of xe2x88x9225 to xe2x88x9240xc2x0 C. for at least 24 hours. Deep-freezing is not effective at a temperature above xe2x88x9225xc2x0 C. Deep-freezing at less than xe2x88x9240xc2x0 C. is undesirable for efficiency.
Preferably, the step of washing peppers is followed by surface sterilization using an appropriate sterilant. This step is more advantageous when contamination of the peppers by microorganisms is serious.
It is preferable that sterilizing the surfaces of the peppers is performed with a 0.1-0.5% sodium dichloroisocyanurate solution for at least 1 minute. The sterilization effect is poor at a sterilant concentration less than 0.1%, and use of the sterilant having a concentration greater than 0.5% is undesirable for economical reasons.
In sterilizing cut peppers separated from the seeds using the chemical sterilant solution and/or high-temperature and high-pressure steam, it is preferable that sterilizing the peppers using the chemical sterilant solution is performed with a 0.4-1.0% sodium dichloroisocyanurate solution for at least 30 seconds. The sterilization effect is poor at a sterilant concentration less than 0.4%, and use of the sterilant having a concentration greater than 1.0% is undesirable for economical reasons.
It is preferable that sterilizing the peppers using the high-temperature and high-pressure steam is performed at a temperature of 90-120xc2x0 C. for 1-10 minutes.
If the sterilization temperature is less than 90xc2x0 C., the sterilization effect is poor. If the sterilization temperature is above 120xc2x0 C., there is a problem of quality degradation due to softening of the structures of the peppers.
It is preferable that, when sterilizing the peppers is sequentially performed using the chemical sterilant solution and the high-temperature and high-pressure steam, sterilization using the chemical sterilant solution is performed using a 0.1-0.5% sodium dichloroisocyanurate solution for 5-20 minutes and sterilization using the high-temperature and high-pressure steam is performed at a temperature of 90-120xc2x0 C. for 2-10 minutes. If sterilization using the chemical sterilant solution is performed using sodium dichloroisocyanurate solution having a concentration less than 0.1% for 5 minutes or less, the sterilization effect becomes poor. If sterilization using the chemical sterilant solution is performed using sodium dichloroisocyanurate solution having a concentration greater than 0.5% for 20 minutes or more, efficiency with respect to the sterilization effect is low.
Preferably, the dried pepper preparation method further comprises mixing the sterilized peppers with a sugar solution between sterilization using the chemical sterilant solution and sterilization using the high-temperature and high-pressure steam. Mixing with the sugar solution improves the appearance of final products and anti-moisture absorption and provides rigid structure.
For a sugar solution widely used in a conventional method, such as a glucose solution, there is a problem of particle aggregation after drying due to a characteristic of the glucose solution. The glucose solution provides poor anti-moisture absorption. Quality of the resultant dried peppers as an individual item is poor, and suitability for secondary processing is undesirable. In contrast, the sugar solution used in the preparation method according to the present invention, whose composition ratios were determined by trial and error, provides significant improvements in physical properties, appearance, and anti-moisture absorption. The sugar solution according to the present invention provides distinct color and improved anti-moisture absorption, and reduces stickiness by including a mixture of trehalose and dextrin, instead of glucose. Preferably, the sugar solution comprises 30-60% by weight of trehalose, 10-40% by weight of dextrin, and 10-40% by weight of purified water, and the sugar solution is added in an amount of 1-10 kg per 20 kg peppers. The composition ratio of the sugar solution and the mixing ratio with peppers are optimized for effectiveness and efficiency.
In drying sterilized peppers by hot air or freeze-drying, it is preferable that hot air drying is performed through two steps to solve a problem of longer drying time for batch drying and to prevent quality degradation. Freeze-drying is advantageous in that unique flavor and texture of the dried red peppers can easily be restored by the addition of boiling water.
It is preferable that drying the sterilized peppers by hot air comprises a first drying performed at a temperature of 90-110xc2x0 C. and a second drying performed at a temperature of 60-95xc2x0 C. These temperature ranges are optimized in view of economics and product quality.
It is preferable that drying the sterilized peppers by freeze-drying is performed at a temperature of 45-70xc2x0 C. for 18-23 hours in a freeze dryer after deep-freezing the sterilized peppers. If the freeze-drying is performed at less than 45xc2x0 C., the cost increases due to an extended drying type. If the freeze-drying is performed above 70xc2x0 C., there is a problem of quality degradation.
It is preferable that the dried pepper preparation method further comprises detecting and separating foreign materials from the dried peppers using a laser before grinding the dried peppers, and separating iron particles from the peppers after grinding the dried peppers. In this case, foreign materials including iron particles, which remain after the sterilization and washing steps, can fully be removed.
In another aspect of the object of the present invention, there is provided an apparatus for hygienically preparing dried peppers by continuous sterilization and drying processes, comprising: an aging room for screening fresh peppers and aging screened peppers to enhance flavor and color of the peppers; a washer for washing foreign materials and pesticide residue from the surfaces of the peppers with water; an optional chemical sterilizer for sterilizing the surfaces of the washed peppers; a cutter for cutting the washed or sterilized peppers into pieces of a uniform size; a seed separator for separating seeds from the cut peppers; a chemical sterilizer and/or a high-temperature and high-pressure steam sterilizer for sterilizing microorganisms existing on the surfaces of and within the peppers; first and second hot air dryers or a freeze dryer for drying the sterilized peppers; and a grinder for grinding the dried peppers into a final product, wherein each unit of the apparatus is connected by a conveyer.
Preferably, the apparatus further comprises a deep-freeze reservoir for storing the fresh peppers, aged peppers, cut peppers, or peppers dried by the first dryer.
Preferably, the apparatus further comprises a laser foreign material detector and separator for detecting and separating foreign materials from the dried peppers before grinding by the grinder, an iron particle separator for separating iron particles from the peppers after grinding by the grinder, and a wrapper.
The dried pepper preparation method according to the present invention includes repeated sterilization and drying processes so that there is no concern about a sanitary problem common to conventional dried peppers. In addition, optional deep-freezing improves storability and preservative quality of the dried peppers so that quality peppers are available throughout the year. By freeze-drying of the peppers, the unique flavor and texture of red peppers can easily be restored by the addition of boiling water.